A forward index lists the words in each document, creating a document-first view of searchable content. It is the starting point for building an inverted index. section 10.3.1
From documents to search
For documents containing “cat” and “cats,” the forward index records each document’s words. Inverting that structure groups each word with the documents containing it, allowing a search for “cat” to jump directly to matches instead of scanning every document. section 10.3.1
A forward index supports the indexing pipeline:
- List words, and optionally their positions, for every document. section 10.3.1
- Invert the listings into a word-to-document structure for efficient retrieval. section 10.3.1
